The inventive concepts relate to semiconductor devices, and more particularly, to semiconductor memory devices.
Since magnetoresistive random-access memories (MRAMs) among resistive memory devices may perform write operations and read operations at high speed, are nonvolatile, and have relatively low power consumption, MRAMs may be used in data storage devices. An MRAM can store data in a variable resistor element, which may be a magnetoresistor element of a memory cell. The MRAM can identify data of a main cell based on a variable resistor element of the main cell and a variable resistor element of a reference cell. As a variable resistance value of a reference cell may be changed due to a continuous read operation, a variable resistance dispersion may be caused in the reference cell, and a data sensing margin of a main cell may be reduced.